Let f(x) = x² +2° (a) On what exact interval(s) is ƒ increasing? decreasing? Make it clear which answers are which, and justify your answers with appropriate supporting work. (b) Find all local maximum and local minimum values of f, giving x and y coordinates with each answer Make it clear which answers are which, and justify your answers with appropriate supporting work.

Calculus: Early Transcendentals
8th Edition
ISBN:9781285741550
Author:James Stewart
Publisher:James Stewart
Chapter1: Functions And Models
Section: Chapter Questions
Problem 1RCC: (a) What is a function? What are its domain and range? (b) What is the graph of a function? (c) How...
icon
Related questions
icon
Concept explainers
Topic Video
Question

I need help with both of these questions 

7. Let \( f(x) = \frac{x}{x^2 + 2} \).

(a) On what exact interval(s) is \( f \) increasing? decreasing? Make it clear which answers are which, and justify your answers with appropriate supporting work.

(b) Find all local maximum and local minimum values of \( f \), giving \( x \) and \( y \) coordinates with each answer. Make it clear which answers are which, and justify your answers with appropriate supporting work.
Transcribed Image Text:7. Let \( f(x) = \frac{x}{x^2 + 2} \). (a) On what exact interval(s) is \( f \) increasing? decreasing? Make it clear which answers are which, and justify your answers with appropriate supporting work. (b) Find all local maximum and local minimum values of \( f \), giving \( x \) and \( y \) coordinates with each answer. Make it clear which answers are which, and justify your answers with appropriate supporting work.
## Problem 9

Let \( f(x) = \frac{2x}{x^2 + 5} \). Below, you are given the first and second derivatives of \( f \); you need not calculate them yourself.

\[
f'(x) = \frac{-2(x^2 - 5)}{(x^2 + 5)^2} \quad \text{and} \quad f''(x) = \frac{4x(x^2 - 15)}{(x^2 + 5)^3}.
\]

### Questions

(a) **On what intervals is \( f \) increasing? decreasing?** 

Make it clear which answers are which, and justify your answer by including an appropriate sign chart as part of your work.

(b) **Find all local maximum and local minimum values of \( f \), giving both \( x \) and \( y \) coordinates in each case.**

Please make it clear which answers are which. 

---

### Explanation

- **First Derivative \( f'(x) \):** This determines where the function \( f(x) \) is increasing or decreasing. A positive derivative indicates that \( f(x) \) is increasing, while a negative derivative indicates it is decreasing.

- **Second Derivative \( f''(x) \):** This helps identify concavity and potential points of inflection. Positive values indicate the graph is concave up, while negative values indicate concave down.

- **Sign Chart:** Use a sign chart for \( f'(x) \) to find intervals of increase and decrease. Look for critical points where \( f'(x) = 0 \) or is undefined.

- **Local Extrema:** Critical points from the first derivative and test using the second derivative or sign changes to determine if they are maxima or minima.

Use the given derivatives to solve the problem based on the intervals where these expressions change sign.
Transcribed Image Text:## Problem 9 Let \( f(x) = \frac{2x}{x^2 + 5} \). Below, you are given the first and second derivatives of \( f \); you need not calculate them yourself. \[ f'(x) = \frac{-2(x^2 - 5)}{(x^2 + 5)^2} \quad \text{and} \quad f''(x) = \frac{4x(x^2 - 15)}{(x^2 + 5)^3}. \] ### Questions (a) **On what intervals is \( f \) increasing? decreasing?** Make it clear which answers are which, and justify your answer by including an appropriate sign chart as part of your work. (b) **Find all local maximum and local minimum values of \( f \), giving both \( x \) and \( y \) coordinates in each case.** Please make it clear which answers are which. --- ### Explanation - **First Derivative \( f'(x) \):** This determines where the function \( f(x) \) is increasing or decreasing. A positive derivative indicates that \( f(x) \) is increasing, while a negative derivative indicates it is decreasing. - **Second Derivative \( f''(x) \):** This helps identify concavity and potential points of inflection. Positive values indicate the graph is concave up, while negative values indicate concave down. - **Sign Chart:** Use a sign chart for \( f'(x) \) to find intervals of increase and decrease. Look for critical points where \( f'(x) = 0 \) or is undefined. - **Local Extrema:** Critical points from the first derivative and test using the second derivative or sign changes to determine if they are maxima or minima. Use the given derivatives to solve the problem based on the intervals where these expressions change sign.
Expert Solution
Step 1

a)fx=xx2+2

Differentiate with respect to x

f'x=x2+21-x2xx2+22=2-x2x2+22

critical points, f'(x)=0

2-x2x2+22=0x=±2

steps

Step by step

Solved in 3 steps

Blurred answer
Knowledge Booster
Sample space, Events, and Basic Rules of Probability
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, calculus and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781285741550
Author:
James Stewart
Publisher:
Cengage Learning
Thomas' Calculus (14th Edition)
Thomas' Calculus (14th Edition)
Calculus
ISBN:
9780134438986
Author:
Joel R. Hass, Christopher E. Heil, Maurice D. Weir
Publisher:
PEARSON
Calculus: Early Transcendentals (3rd Edition)
Calculus: Early Transcendentals (3rd Edition)
Calculus
ISBN:
9780134763644
Author:
William L. Briggs, Lyle Cochran, Bernard Gillett, Eric Schulz
Publisher:
PEARSON
Calculus: Early Transcendentals
Calculus: Early Transcendentals
Calculus
ISBN:
9781319050740
Author:
Jon Rogawski, Colin Adams, Robert Franzosa
Publisher:
W. H. Freeman
Precalculus
Precalculus
Calculus
ISBN:
9780135189405
Author:
Michael Sullivan
Publisher:
PEARSON
Calculus: Early Transcendental Functions
Calculus: Early Transcendental Functions
Calculus
ISBN:
9781337552516
Author:
Ron Larson, Bruce H. Edwards
Publisher:
Cengage Learning